Dendritic complexity, synaptogenesis, and overall proper development and function of neurons are regulated by growth factors such as brain derived neurotrophic factor (BDNF). Estrogen (specifically, estradiol) is an example of a small molecule that is known to promote dendritic spine density in rodents and has been shown to improve cognition in humans. Unfortunately, the well-documented, harmful, long-term effects (e.g., increased risk of cancer, stroke and heart disease) of estrogen therapy preclude its general use for treating neuronal diseases. Disclosed herein, inter alia, are solutions to these and other problems in the art.